In the construction of concrete structures, such as building foundations and concrete walls, it is often desirable to provide Insulation to the exterior surface of the concrete. In the industry, exterior insulation is usually preferred over interior insulation in that it generally permits complete coverage of the structure without the difficulty of running service conduits such as plumbing and electrical wiring through the insulation, as is required with interior insulation. Moreover, exterior insulation can be completed without entering the structure and does not reduce interior floor space.
Exterior insulation is also advantageous over interior insulation in that it reduces temperature fluctuations in the concrete wall, can improve the energy efficiency of the building as well as reducing noise travel through the walls of the structure. Still further, and in the particular case where aluminium forms are used for creating the structure, when the exterior surface of a concrete wall has been insulated, the interior surface of the concrete foundation, by virtue of the smooth finished surface that an aluminium form provides, requires only light plastering to provide a finished wall surface on the Interior of the structure.
As is known, when a concrete foundation or building Is constructed, concrete is poured between removable forms that are held in place by a two-dimensional array of metal ties passing through the forms that hold and support the forms until the concrete has set. After the forms are removed, the ends of the metal ties are broken off at the surface of the structure to provide a smooth wall. The interior and/or exterior surface of the structure may be insulated by various methods using different types of insulation. Such methods may include affixing rigid insulation panels to the interior or exterior surface of the concrete wall, spraying foam onto the exterior surfaces or by building supporting walls for holding flexible insulation bats. For example, U.S. Pat. No. 6,434,902 teaches the fastening of caps to form ties of a concrete wall to hold the rigid insulation panels against the concrete wall.
One drawback of rigid insulation panel systems, particularly in the residential construction industry, is the difficulty in anchoring exterior finishing surfaces such as vinyl siding to the exterior surface of the insulated structure. In addition, the panels are awkward to transport and manoeuvre into place, often requiring the panels to be slid past a retaining system or to be held in place while a retaining system is affixed to the structure.
More recently, the residential construction industry has benefited from the development of Insulating Concrete Form (ICF) systems, in which rigid insulation panels are stacked and held in place by plastic or metal ties to create a form into which concrete is poured. In the finished structure, the ties extend through the foam to provide a nailing strip to enable the attachment of drywall to the interior surface, and exterior finish (such as vinyl siding) to the exterior surface of the wall.
The prior art includes examples of ICF systems, such as U.S. Patent Application No. 2002/0124508 and U.S. Pat. No. 6,647,686, which disclose a stud system for attachment to insulating concrete forms prior to pouring of the concrete. Spreaders are attached to the studs to hold apart the insulated panels until the concrete cures.
U.S. Pat. No. 5,819,489 discloses a flow-through stud system for use between the panels of an insulating concrete form system. The studs, when assembled, are generally I-shaped and have a web-like structure to allow newly poured concrete to disperse through the stud system. The insulated concrete forms are left in place to become the exterior surface of the wall.
U.S. Patent Application No. 2001/0002528 discloses a spacing web frame assembly or stud system for holding apart insulating concrete forms. The studs are connected by a reinforcing wire web that extends from one stud to the other, thereby holding apart the forms and allowing concrete to be poured between the forms.
U.S. Patent Application No. 2003/0033782 discloses a wall tie bracket for providing spacing between insulating concrete forms, replacing the need for form ties and creating a void between the forms into which concrete is poured.
U.S. Pat. No. 3,730,476 discloses a system for forming concrete. The studs used with the system are generally extruded U-shaped metal studs, and are provided with spaced apart holes to accommodate snap ties which extend therethrough and are releasably held by ordinary fastening wedges. The studs are removed following curing of the concrete, and are not intended to support exterior insulation or exterior finishes.
U.S. Patent Application No. 2002/0178676 discloses a method to assemble insulating concrete forms such that the forms (with attached studs) are held in place while the concrete is poured.
In general, ICF's are costly and somewhat fragile, so care must be taken during concrete pouring to prevent bulging, shifting or breakage of the ICF's. Moreover, the limited strength of ICF's does not allow for proper vibration of the forms to consolidate the concrete, resulting in voids and honeycomb within the finished concrete structure. The forms are also generally of an awkward size, making transport and storage inconvenient.
It is therefore desirable to provide an improved system for insulating the surfaces of concrete structures that enhances the application of spray foam to a concrete surface to both support the insulation and provide further finishing options.